Abrasive element



ABRAS IVE ELEMENT Filed Feb. 28. 1954 INVENTOR.

A'I'I'ORNEYJ Patented Mar. 3, 1936 UNITED STATES PATENT o FFICEV 6 Claims.

The present invention, relating as indicated to an abrasive element, is more particularly directed to a new and improved seamless tubular abrasive sleeve for use in the polishing and finishingof surfaces of high degrees of finish and accuracy, and to a new method of manufacturing a sleeve for this purpose. Another object of the invention is the provision of a sleeve which will be without breaks or interruptions in the abrasive surface and have a diametral accuracy permitting its use on closely dimensioned mandrels for the accurate finishing of such articles as small parts formed of brass and similar soft metal, and the finishing of other articles, such by any suitable means as stainless steel sheets, tubes and the like.

To the accomplishment of the foregoing and related ends, said invention, then, consists of the means hereinafter fully described and particularly pointed out in the claims; the annexed drawing and the following description setting forth in detail certain means and one mode, also one product, constituting, however, but one of various applications of the principle of my invention.

,In said annexed drawing:-

Fig. 1 is a view in perspective of my improved abrasive element; Fig. 2 is a similar view showing the same mounted upon a mandrel for sizing; and Fig. 3 is a view more or less diagrammatic in character illustrating one method of coating tubular reenforcing material with abrasive.

Referring now to Fig. 1, I have shown a seamless tubular fabric element I woven in cylindrical form of any suitable material which may be of any suitable thickness, but is ordinarily of the character of a fairly heavy canvas material. These tubes or sleeves I are next moistened and stretched upon sizing mandrels 2, as illustrated in Fig. 2, where they are allowed to dry to approximately the exact desired size. I find that more accurate sizing can be secured by this method than by the usual step of shrinking.

The sized but uncoated sleeves I are next coated uniformly all over their outer surface with adhesive and abrasive, and in Fig. 3 I have. illustrated one type of apparatus for carrying out this step in the manufacture of the desired abrasive element. There is there shown a base 3|, upon which is rotatably mounted a large disk or plate 32 carrying equidistantly spaced mandrels 3, each of which is rotatably mounted on the plate. The plate is provided with a ratchet wheel 4 and into this ratchet wheel engages a pawl 5 hinged to an operating arm 6, which may beactuated to intermittently oscillate,

thereby partially rotating the disk or plate 32 and the mandrels carried thereby through an angle determined by the oscillatory movement which is given to the arm 6. Movement is imparted to the arm 6 by means of a pin I carried by this arm and operating in a cam track 8, carried on a constantly rotating hub 9 attached to a shaft I0, on which the entire plate is rotatably mounted. For each rotation of the shaft I0 and cam track 8 the pin I is actuated in a clockwise direction, pulling the arm 6 in the same direction and rotating the disk 32 through a predetermined portion of one revolution.

Mounted at one side of the machine is a reservoir II containing adhesive I2, moistening the surface of an adhesive roll I3 mounted in a position to spread adhesive over the surface of a sleeve I mounted on the mandrel 3 in registration with the roll I3. The entire plate or disk is operated to bring one of the mandrels 3, upon which has been mounted a sleeve I,:into registering position with the adhesive roll I3 when the plate is held by means of a latch I5 operated by means of a rod IGandcontrolled by means of a cam I1, also carried on the rotating shaft on which the rotary disk is mounted.

When the plate is stopped with one of the mandrels 3 in registering position with the adhesive roll I3, the movement of the mandrel into this position throws, into engagement a gear I8 on the mandrel with the gear I9, carried by a constantly running motor 20, and thereby the man-v drel is caused to operate in contact with the adhesive roll, rotating the latter, and causing it to pick up acoating of adhesive which is then uniformly transferred to the surface of the sleeve I on the mandrel. Continued motion of the disk brings the adhesively coated sleeve, first to the station 2| and then to the station 22 beneath a hopper 23 containing abrasive, and when brought to this position the gear'on the mandrel 3 again engages with the gear 24 on a second continuously running motor 25, causing the sleeve to be rotated beneath the discharge spout 26 of the abrasive hopper, and in this way abrasive is uniformly coated over the entire adhesively coated surface of the sleeve. Continued rotation of the disk finally brings the abrasive coated sleeve to one of the lower positions shown in Fig. 3, at which point it may be removed and set aside for drying.

Various other forms of mechanical forms of apparatus may be employed for the coating of the formed and sized fabric sleeves, and also it is obvious that the prepared sleeves may be coated manually if desired.

The present abrasive sleeve represents a distinct improvement over those now in use because of its unbroken surface, its uniform strength, its thinness and the accuracy to which it may be formed, and I have found it possible to produce sleeves to exact given dimensions with a tolerance of .005 of an inch plus or minus the required diameter. Heretofore sleeves made with lapped joints or interfltting joints which are reenforced, have been so inaccurate that after manufacture they had to be sorted out into three general sizes and three times as much stock carried as required. In addition, an oversized sleeve could in many cases not have been used on a standard or slightly undersize mandrel or support, and in all cases of such inaccuracy the effect upon the work was detrimental. In addition to this objection, sleeves formed of superimposed spirally wound strips, while reasonably accurate, have to be made of thicker material than my improved sleeve here described, and are frequently sufllciently irregular along the edges of contact of adjacent convolutions of the spiral strips to prevent higher polishing which is now required on such articles as stainless steel sheets, tubes and the like, which in some cases require what is termed a mirror finish.

Other forms may be employed embodying the features of my invention instead of the one here explained, change being made as regards the means and the steps herein disclosed, provided the elements stated by any of the following claims or the equivalent of such stated elements be employed, whether produced by my preferred method or by others embodying steps equivalent to those stated in the following claims.

I therefore particularly point out and distinctly claim as my invention:-

1. In a method of making abrasive sleeves, the steps which consist in forming a seamless fabric tube, moistening and drying said tube while supported internally, and adhesively applying abrasive to the outer surface thereof.

2. In a method of making, abrasive sleeves, the steps which consist in forming a seamless fabric tube, stretching the sameto a predetermined diameter, and then adhesively applying abrasive to the outer surface thereof.

I 3. In a method of making abrasivesleeves, the

steps which consist in forming a seamless fabric tube, stretching the same to a predetermined diameter, adhesively applying abrasive to the outer surface thereof, and then cutting said tube into predetermined lengths.

4. A new article of manufacture consisting of a one-piece seamless tubular fabric sleeve provided with a coating of abrasive adhesively secured to the outer surface thereof, the fabric of said sleeve being pre-stretched to a given diameter.

5. In a method of making abrasive sleeves, the

7 steps which consist in forming a seamless fabrictube, moistening said tube, stretching said tube over a supporting surface of predetermined and uniform .diameter, drying said tube while so stretched and supported, and then adhesivelyapplying abrasive to the outer surface thereof.

6. In a method of makng abrasive sleeves, the steps which consist in forming a seamless canvas tube, moistening said tube, stretching said tube over a supporting surface of predetermined and uniform diameter, drying said tube while so stretched and supported, and then adhesively applying abrasive to the outer surface thereof.

' WILLIAM J. ELLIS. 

